Furnace construction



Feb. 24, 1931. w. F. DETWILER FURNACE CONSTRUCTION Filed April 27. 1928 2 Sheets-Sheet 1 INVENTOR. wild/m 8% JAM ATTORNEYS.

Feb. 24, 1931. w. F. DETWILER 1,793,913

FURNACE conswnucwxon Filed April 27, 1928 2 Sheets-Sheet 2 INVENTOR.

BY 9 92 W 414/. ATTORNEYS.

Patented Feb. 19 31 UNITED STATES PATENT OFFICE WILLIAM IE. DETWILER, OF TABENTUM, PENNSYLVANIA, ASSIGNOR T0 ALLEGHENY STEEL COMPANY, A CORPORATION OF PENNSYLVANIA FURNACE CONSTRUCTION Application filed April 27,

Thisinvention relatesto furnaces and more particularlyto an improvementin the construction of furnaces for heat treating sheet metal and the like.

Heating furnaces in general have heretofore been constructed of fire brick or blocks of like refractory material, or they have been provided with a lining. of fire brick or like refractory material. Such materials, when subjected to great heat, expand and contract and cause cracks allowing heat to escape from the furnace. Such material as fire brick and the like does not only crack under the condition of expansion and contraction, but spells and falls in contact with the materialbeing treated, resulting in undesirable marking of such material; All ofthe furnacesknown to me that are constructed from fire brick or have a lining of fire-brick or like refractory material frequently fuse and burn out and of course it is necessary to be continually repairing such furnaces. This is not only expensive, but renders the furnace inoperative dur ing such frequent repairs. Also in furnaces designed for heat treating sheet metals, it is necessary for such metals to come in contact with the inner side walls of the furnace and such contact is very detrimental to the refractory walls and it is one object of this invention to provide a furnace, wherein. the inner side walls are constructed of metal having sufficient refractory characteristics to withstand the heat of the furnace, retain the static pressure therein, eliminate cracks in the furnace walls, eliminate the hazard of foreign material coming in contact with the sheets of metal being treated and eliminate the need of frequent repairs. 1

I have found through experience that sheets of ferrous alloys containing 8% of chromium or above possess the required refractory characteristics for use as lining in heating furnaces and that such sheets will not crack under the conditions of expansion and contraction, nor do such sheets spall or fall in con tact with the material being treated, also such refractory sheet metal, when employed as a lining for heating furnaces, will last indefinitely and thereby eliminate the expense of frequently repairing such furnaces as is the 1928 Serial no. 273,256.

case when fire brick or like refractory materials are employed. 1

Another object of this invention is to provide a heating furnace that shall be simple and rugged in structure, inexpensive to manufactureandmore. efficient in operation than any furnace heretofore known to me.

These and other objects that may be made apparent throughout the further description of theinvention are attained by means of the furnace illustrated in the accompanying drawings, wherein, 1

Fig. 1 is a longitudinalsectional View more or less diagrammatic of a furnace embodying the invention, and i :Fig. 2 is a sectional view taken along the line IIII of Figure 1.

:The present invention may be employed in the construction. of furnaces of any desired shape or form and for the purpose of illustration, I have shown a furnace constructed for heating sheet metal. The furnace comprises a fire compartment 11 and a heating compartment 12. The conventional. bridge wall 13 is provided between the compartments 11 and 12 and have associated therewith ashbaflles 14 and 15.

The side walls and the topof the furance comprise a double metal wall 16 and 17 spaced apart having any suitable insulating material 18 disposed therebetween. The inner wall 16 is formed from sheets made from a ferrous alloy containing a high per cent of chromium and possessing the desired refractory characteristics for withstandinggreat heat. The outer wall 18 may he of any suitable metal, such as steel and the insulation 18 may be either silica sand or fire brick 19, as shown within the bridge wall 13.

i The furnace is preferably disposed on a cementfoundation, as shown at 21. The heating compartment 12 is provided with a floor of refractory sheet metal 16 supported by metal supports 22 which are in turn support-v ed by a steel plate 23. Between the steel plate 23 and the concrete foundation 21 is dis- "posed any suitable insulating material as 18.

The fire compartment 11 is provided with a a stoker 24: and grate 25 which is adapted to operate in the convenient manner. The entire inner walls of both the fire compartment 11 and the heating compartment 12, as well as the baffles 14 and 15, are constructed of the refractory sheet-metal 16,

An opening 26 is provided in front of the V compartment 12 for inserting and withdrawing sheet metal to and from the furnace.

' The opening 26 is provided with avsuitable door 27 constructed of the same, material as the side walls and provided with'any suitable means, such asshown at'28 for raising and lowering it. 1

The arrows indicate the direction of movement of the gases through the furnace.

The gases in their passage from the fire compartment 11 .to' the heating compartment 12 pass around through the passages 31 andf32 formed "by the bridge wall 13 and bafiies 14 and 15 and during such passage are freed from foreign substances such as ashe's, which are'retained atthe bottom of the compartment '33 formed by the bridge wall 13 and baffle 15,- the compartment 33 is 7 provided with a door 34 for removing such ashes therefrom. The gases circulate Within the compartment 12 and pass out through openings provided in the floor-of the compartment '12 throughthe ducts 26 beneath the floor-and out the stack 37.

If have found through eXperie-ncethat a heating furnace constructed 1n accordance ent'construction is-that the static pressure is positively retained within the furnace and thereby renders the heating of metals in such furnace more uniform, efiicient and less eX- pensive.

' Other advantages will be apparent to those skilled in'the art, such as the elimination of the undesirable marking of the metals being treated-by the dropping out of particles of the inner'walls-as is the case when fire brick or other like refractory materials are employed. VVhile 1 haveillustrated and described, but one embodiment of this-invention, it will be apparent 'to those skilled in the art that certain'changes, modifications, substitutions, ad,- ditions and omissionsm ay be made in the invention without departing from the spirit and-scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1;- A' heating furnacehaving in combina tionacombustion chamber, a heating chain- 7 least 8% chromium, and

The inner chamber-to a point nearithe top thereof, a

second ash baffle extending from the top of said heatin chamber between said bridge wall and first mentioned ash baffle to a point near the bottom thereof, said ash baffles and 7 bridge wallforming a passage for the prodnets of combustion for delivering said gases to the topof said heating chamber and time 7 under said heating chamber for drawing the exhausted combustion gases from said heating chamber. H Y

2. In a heating furnace having, a combustion chamber, a heating chamber and a bridge wall, a lining for said'chambcrs and a cover for said bridge wall formed from a sheet of ferrous alloy containing about'8% chromium and an ash baffle formed from a sheet of said alloy separating'said combustion chamber from said heating chamber.

3. In a heating furnace having a combustion chamber, a heating chamber and a bridge wall, a sheet metal lining for the heating chamber and a cover for-the bridge wall formed from a ferrous alloy containing at ash baffle separating the combustion chamber from the heating chamber and formed from sheet metal of the same alloy. with the above will last indefinitely and pro- 4e, l'n'a heating-furnace having a comb u, tion'chamber, a'heating chamber, a bridge wall and an ash bafiie separatingthe combus tion chamber from the heating chamber, a lining forthe heating chamber and a cover for the bridge wall;said lining, cover and ash baffle being formed from ferrous alloy sheets contaiiiing at least 8% chromium,

In a heating furnace having a combus tion chamber, a heating chamberand a-bricge wall, a lining for said: chambers and a cover for said bridge wall formed from sheet ferrous alloy cont-ainingiat least 8% chromium.

In testimony whereof, I have scribed 111 name this 24th day of April, 1928.

1V ILLIAM F. DETl VILER.

hereunto sub 

